Most U.S. House members easily won re-election last week. View partisan composition for each state.

While the close presidential vote and several narrowly-contested Senate races occupied the public spotlight last Tuesday, the vast majority of House incumbents easily coasted to victory.

The election – the first since 2010 redistricting – saw few competitive House races in a year when the nation remained mostly evenly split. Some incumbents benefited from high name recognition and weak challengers. Others, though, had the scales tipped in their favor when party officials drew new Congressional maps intended to limit their vulnerability.

California and Florida introduced reforms into the process, and the two states saw several races decided by razor-thin margins. By and large, though, voters sent delegations to Congress with roughly the same partisan makeup as before as incumbents enjoyed protection after redistricting.

Only 64 of the 435 House races were decided within a 10 percentage-point margin, according to a Governing review of elections data. Of all incumbents vying to retain their seats in the general election, just 21 had been defeated as of Tuesday. In 2010, 79 House races had margins of victory less than 10 percent and 54 incumbents lost.

Although some races proved to be more competitive after redistricting, they weren’t close enough to flip control of seats.

“Parties were recognizing that you didn’t need these incredibly safe districts in every state to retain control,” said Keesha Gaskins, a senior counsel at the Brennan Center for Justice who studies voting issues.

Despite Democratic victories in swing states, Republicans retained a firm hold on control of the House.

Seven states voted for one party for president, but sent a House delegation majority of the opposite party – all of which favored Republicans in states casting electoral votes for president Obama.

In three blue states where Democrats also won Senate races – Ohio, Pennsylvania and Virginia – Republicans won about three-quarters of all House seats. The GOP also claimed the majority of seats in Colorado, Florida, Michigan and Wisconsin.

With the exception of Colorado, Republican-led state legislatures controlled the redistricting process in all seven of these states voting for Obama. Nationwide, Republicans drew lines for more than 200 seats – four times more than Democrats.

But how much did redistricting actually swing control of the House in their favor?

A study published last month by the Brennan Center for Justice, which Gaskins co-authored, estimated Republicans’ ability to set new district lines put them in position to control 11 additional seats prior to redistricting. Republicans particularly sought to protect vulnerable freshman lawmakers. The number of freshmen Republicans in districts normally electing Democrats fell from 14 to 6 after redistricting, the report found.

Nate Persily, a redistricting expert and political science professor at Columbia Law School, offered a similar assessment: “In general, Republicans shored up their incumbents instead of being too greedy, and that’s all they needed to do."

The following table shows partisan composition of House members for each state, along with how the state voted in the presidential election. Numbers do not include undecided House races in Arizona, California and North Carolina.

State

Drawer

Obama %

Romney %

Rep. House %

Dem. House %

2012 Dem.

2012 Rep.

Alabama

Legislature/Gov. Rep. control

38.4

60.7

85.7

14.3

1

6

Alaska

None

41.6

55

100

0

0

1

Arizona

Independent Commission

43.8

54.6

44.4

44.4

4

4

Arkansas

Legislature/Gov. Dem. control

36.9

60.5

100

0

0

4

California

Independent Commission

59.1

38.5

28.3

67.9

36

15

Colorado

Court

51.2

46.5

57.1

42.9

3

4

Connecticut

Court

58.4

40.4

0

100

5

0

Delaware

None

58.6

40

0

100

1

0

Florida

Legislature/Gov. Rep. control

49.9

49.2

63

37

10

17

Georgia

Legislature/Gov. Rep. control

45.4

53.4

64.3

35.7

5

9

Hawaii

Political commission

70.6

27.8

0

100

2

0

Idaho

Independent Commission

32.6

64.5

100

0

0

2

Illinois

Legislature/Gov. Dem. control

57.3

41.1

33.3

66.7

12

6

Indiana

Legislature/Gov. Rep. control

43.8

54.3

77.8

22.2

2

7

Iowa

Independent Commission

52.1

46.5

50

50

2

2

Kansas

Court

37.8

60

100

0

0

4

Kentucky

Legislature/Gov. Divided control

37.8

60.5

83.3

16.7

1

5

Louisiana

Legislature/Gov. Rep. control

40.6

57.8

83.3

16.7

1

5

Maine

Legislature/Gov. Divided control

56

40.9

0

100

2

0

Maryland

Legislature/Gov. Dem. control

61.7

36.6

12.5

87.5

7

1

Massachusetts

Legislature/Gov. Dem. control

60.8

37.6

0

100

9

0

Michigan

Legislature/Gov. Rep. control

53.8

45.3

64.3

35.7

5

9

Minnesota

Court

52.8

45.2

37.5

62.5

5

3

Mississippi

Court

43.5

55.5

75

25

1

3

Missouri

Legislature/Gov. Divided control

44.3

53.9

75

25

2

6

Montana

None

41.8

55.3

100

0

0

1

Nebraska

Legislature/Gov. Rep. control

37.8

60.5

100

0

0

3

Nevada

Court

52.3

45.7

50

50

2

2

New Hampshire

Legislature/Gov. Rep. control

52.2

46.4

0

100

2

0

New Jersey

Political commission

58

40.9

50

50

6

6

New Mexico

Court

52.9

43

33.3

66.7

2

1

New York

Court

62.6

36

22.2

77.8

21

6

North Carolina

Legislature/Gov. Rep. control

48.4

50.6

69.2

23.1

3

9

North Dakota

None

38.9

58.7

100

0

0

1

Ohio

Legislature/Gov. Rep. control

50.1

48.2

75

25

4

12

Oklahoma

Legislature/Gov. Rep. control

33.2

66.8

100

0

0

5

Oregon

Legislature/Gov. Divided control

54.3

42.8

20

80

4

1

Pennsylvania

Legislature/Gov. Rep. control

52

46.8

72.2

27.8

5

13

Rhode Island

Legislature/Gov. Dem. control

62.7

35.5

0

100

2

0

South Carolina

Legislature/Gov. Rep. control

44

54.6

85.7

14.3

1

6

South Dakota

None

39.9

57.9

100

0

0

1

Tennessee

Legislature/Gov. Rep. control

39

59.5

77.8

22.2

2

7

Texas

Legislature/Gov. Rep. control

41.4

57.2

66.7

33.3

12

24

Utah

Legislature/Gov. Rep. control

24.9

72.8

75

25

1

3

Vermont

None

67

31.2

0

100

1

0

Virginia

Legislature/Gov. Rep. control

50.8

47.8

72.7

27.3

3

8

Washington

Independent Commission

55.5

42.2

40

60

6

4

West Virginia

Legislature/Gov. Dem. control

35.5

62.3

66.7

33.3

1

2

Wisconsin

Legislature/Gov. Rep. control

52.8

46.1

62.5

37.5

3

5

Of course, one can’t expect voters to cast ballots along identical party lines in each race. Persily said comparing presidential and statewide elections results to the composition of House members is more meaningful, though, than examining party vote totals for House races in a given state, since so many races are lopsided.

Constitutional requirements give states significant leeway in how they draw districts, but some are subject to provisions of the Voting Rights Act, aimed at ensuring the full enfranchisement of minority voters.

Most states losing seats through reappointment, based on population counts from the 2010 Census, were traditionally Democratic. Republicans in these states generally eyed seats occupied by Democrats for consolidation as they drew new maps, Persily said.

The Republican-controlled Missouri Legislature approved a map cutting out the St. Louis district of Rep. Russ Carnahan as the state lost one seat this cycle. Gov. Jay Nixon, a Democrat, vetoed the proposal, but the Legislature overrode the veto with the help of a few Democrats who said they wanted to protect their colleagues in Congress.

John Judd, a GOP committeeman and district director for Missouri state Senator Jim Lembke, told Governing lawmakers sought to draw a map that would send six Republicans to Congress (of the state’s eight seats) by packing as many St. Louis Democrats as possible into a single district.

"The lines are totally drawn for partisan advantage,” he acknowledged. “If you have the pen in your hand, you draw the map as you choose.”

Judd said his party drew the map to lean Republican because Democrats would have done the same.

"You can’t really remove the politics from [redistricting] as long as it’s a bill process," he said.

Similarly, only one of New Jersey’s 12 congressional races was even close – decided by eight percentage points. Democrats ended up losing a seat as the state’s delegation shrank from 13 to 12. Tom Bonier, a redistricting expert who worked with Democrats in the state, penned a sharply-worded editorial criticizing the redistricting process.

But Republicans weren’t the sole beneficiaries of redistricting – Democrats picked up a handful of seats in states where they controlled the process.

In Illinois, the Democratic-led Legislature carved out a new map and the party gained four seats, while Republicans lost five.

Maryland Republicans denounced Democrats’ new congressional map for their state, which features odd-shaped districts and twisting boundary lines. A recent analysis by geospatial firm Azavea showed the state’s districts, using three different metrics, were the least compact of any state. Republicans fought back by organizing a ballot measure challenging the proposed districts, but voters overwhelming OK’d the Democratic-backed map last week.

Florida and California took a different approach as voters passed ballot measures aimed at shaking up the redistricting process.

Sen. Don Gaetz, a Republican who chaired the state Senate’s redistricting committee, said lawmakers started from scratch with a blank map and sought to draw lines that did not split communities across multiple districts. The committee held public hearings throughout the state and the proposed maps easily passed in the Republican-controlled House and Senate.

“We set out to create the most open and inclusive process in our state’s history, and I believe we achieved that,” Gaetz said.

Florida Democrats ended up picking up four seats and Republicans lost two. Gaetz said the new maps may have cost his party a couple seats, such as Rep. Allen West, a Tea Party favorite who moved his residence to compete in a more conservative district north of West Palm Beach, Fla. West trailed Democrat Patrick Murphy by 2,000 votes in counts earlier this week, but refused to concede.

Despite the defeats, the GOP still won 17 of the state’s 27 Congressional races. Gaetz said he suspects Democratic-leaning groups supporting the redistricting ballot measures were disappointed they couldn’t flip more seats.

“Redistricting matters, but not as much as the quality of candidates and quality of campaigns,” he said.

California adopted an entirely new system by taking redistricting out of the hands of state legislators and turning it over to a citizens’ commission. Commission members, selected from thousands of applicants, drew districts based on testimony from members of each community. The process wasn't flawless, though. ProPublica reported Democrats enlisted labor unions and other groups to testify on their behalf at community meetings to support maps skewed in their favor.

Many of the state’s Congressional elections did end up being competitive, with 11 seats decided within 10 percentage points. Democrats didn’t see much turnover, though, as only three of 34 incumbents lost their races, all to other Democrats.

Other states also made notable strides in giving citizens more clout in redistricting. Nonprofit groups and universities set up public mapping projects, enabling voters to draw and submit their own maps. But, according to Gaskins, it's unclear at this point whether these civic engagement initiatives bore any real fruit or were simply pushed aside by politicians.